Field of the Invention
The invention concerns a method for monitoring a radiation therapy of a patient, as well as a magnetic resonance apparatus and an apparatus for planning irradiation of a target area of a patient in accordance with such a method.
Description of the Prior Art
During the course of a radiation therapy target tissue, for example a tumor, of a patient is irradiated with ionizing radiation. External radiation therapy, wherein irradiation of the patient's body is done from outside the body, is a known procedure for this purpose. Likewise internal radiation therapy, also called brachytherapy, is known. In brachytherapy, radiation sources that embody radioactive substances are introduced into the patient's body in order to damage or to destroy the target tissue locally in the patient's body.
Planning and/or monitoring a radiation therapy of a patient by means of imaging are known. One of the methods used for planning and or monitoring a radiation therapy of the patient is magnetic resonance tomography, by the operation of a magnetic resonance apparatus.
In a magnetic resonance apparatus, also called a magnetic resonance tomography system, the body of a person to be examined is usually exposed, with the aid of a basic field magnet, to a relatively strong magnetic field, of 1.5 or 3 or 7 Tesla, for example. In addition gradient pulses are emitted by a gradient coil arrangement. Radio frequency (RF) pulses, particularly excitation pulses, are then emitted via a radio-frequency antenna arrangement by suitable antennas, which cause nuclear spins of specific atoms in the subject, that are excited resonantly by these RF pulses, to be flipped by a defined flip angle in relation to the magnetic field lines of the basic magnetic field. During the relaxation of these nuclear spins, radio-frequency signals, called magnetic resonance signals, are emitted, which are received by suitable radio frequency antennas and then further processed. From the raw data acquired with this manner, the desired image data can be reconstructed.